struct MaterialUniform {
    modelMatrix : mat4x4 <f32>,
    color : vec3 <f32>,
    opacity : f32,
    normalMatrix : mat4x4 <f32>,
    emissive : vec3 <f32>,
    metallic : f32,
    roughness : f32,
    #if USE_NORMALTEXTURE
        normalTextureScale : vec2 <f32>,
    #endif
    #if USE_AOTEXTURE
        occlusionStrength : f32,
    #endif
}
